Properties and effects of dust particles suspended in the Martian atmosphere

作者：James B. Pollack, D. S. Colburn, F. M. Flasar, Ralph A. Kahn, C. E. Carlston, D. Pidek · 发表于：Journal of Geophysical Research Atmospheres · 年份：1979 · DOI：10.1029/jb084ib06p02929 · 被引用次数：581 · 研究领域：Planetary Science and Exploration、Atmospheric aerosols and clouds、Space exploration and regulation

Direct measurements of the optical depth above the two Viking landers are reported for a period covering the summer, fall, and winter seasons in the northern hemisphere, a time period during which two global dust storms occurred. The optical depth had a value of about 1 just before the onset of each storm; it increased very rapidly, on a time scale of a few days, to peak values of about 3 and 6 with the arrival of the first and second storms, respectively; and it steadily decreased shortly thereafter (≳ few days to few weeks) for both storms, with the decay occurring more rapidly during the initial period of decay. We have also carried out further analyses of observations of the sky brightness made with the lander cameras during the summer season to obtain improved estimates of other dust particle parameters, including the cross section weighted mean particle radius, several shape factors, and the imaginary indices of refraction. These results have been used to define the radiative properties of the suspended dust particles at solar wavelengths. Particle properties inferred by Toon et al. (1977) from their study of the Mariner 9 Iris data were employed to define the radiative properties of the dust at thermal wavelengths. In an effort to understand the effect of dust content on atmospheric temperatures and winds, we have incorporated the derived radiative properties of the dust into a 1 D radiative convective model. When only radiation and thermal convection are taken into ac...